what was your last vehicle? if it was a passenger vehicle - this is normal... when i first began driving my jeep i would brace my back against the seat and stand on the pedal to stop it... however now im learning how to stop it better and coming to grips with manual brakes.

Just a quick point here. Check all parts of the braking system. After going with new rear shoes & wheel cylinders !Properly adjsted! - this is very important, and new rotors & pads on the front, it's like a new Jeep. With 31" tires, my CJ now stops better than my wife's ZJ. Unless its raining, of course. It took me a while to get used to how quickly it would stop.